JP4353758B2 - Container airtightness inspection method and apparatus - Google Patents

Description

  The present invention relates to a container airtightness inspection method and apparatus according to the superordinate concept of independent claims 1 and 7.

  In order to detect the non-tightness of a container filled with fluid, for example a tank device of an automobile with an internal combustion engine, a negative or overpressure is applied to the container. When non-hermeticity is present, this non-hermetic fluid causes fluid to flow into or out of the container, thereby reducing negative or overpressure. Negative or overpressure reduction is used as a measure for non-tightness variables.

  For example, in the case of a tank device for an automobile equipped with an internal combustion engine, a mixture of fuel vapor and air in particular is sucked from the tank device due to the negative pressure in the intake pipe of the internal combustion engine. For this purpose, the tank vent valve between the intake pipe and the tank device is opened. In order to prevent subsequent fresh air (i.e., outside air or outside air) from flowing into the tank device, the fresh air supply pipe of the tank device is closed with a shut-off valve. Subsequently, the tank vent valve is closed, and the negative pressure in the tank device is measured by a pressure sensor located in the tank device. If non-tightness exists in the tank device, ambient air can flow into the tank device, which will reduce the negative pressure.

An airtight test method for a vehicle tank device is known from WO 01/59286. In this method, a negative pressure is generated by the pump.
Negative pressure or overpressure can cause deformation of the elastic components of the tank device, in particular the tank itself, thereby reducing the negative pressure or overpressure in the tank device. This phenomenon, also called creep phenomenon, occurs only once for each component in the formation of negative or overpressure.

  When a negative pressure is formed, a part of the fluid, particularly fuel, present in the container moves from the liquid phase to the gas phase (gas generation) in order to replenish the sucked amount in the gas phase. Gas generation also reduces the negative pressure. Gas generation decreases with increasing fluid volume as a function of fluid vapor pressure and gaseous fluid partial pressure until pressure equilibrium is reached.

When negative or overpressure is applied to a container filled with fluid, gas generation or condensation of the fluid present in the container and / or deformation of the elastic components of the container will reduce the negative or overpressure. This limits the accuracy of the airtight inspection.
International Patent Publication No. 01/59286

  Here, the influence of the elasticity of the container components and / or the gas generation of the liquid present in the container or the condensation of the gas or gas mixture present in the container on the negative pressure or overpressure in the container is reduced. Makes it possible to detect the non-hermeticity of the vessel with a high degree of certainty and to determine the non-hermetic variable with high accuracy, irrespective of the physical and / or chemical process being carried out. It is a technical problem of the present invention to provide an automobile tank apparatus and a tank aeration apparatus having a gas tightness inspection method and apparatus.

The present invention solves this problem by the features of the independent claims 1 and 7. Advantageous forms of the subject of the invention are described in the dependent claims.
According to the invention, a predetermined constant negative or overpressure is applied to the container by the pressure source. In this case, since the pressure source is operated while being controlled, when non-airtightness exists, a constant air mass flow rate (air mass flow) is set on average due to the non-airtightness. Here, in order to keep the negative pressure or the overpressure constant, the pressure source is operated with a constant manipulated variable on average. From this manipulated variable, a non-hermetic variable can be calculated.

  Each supply to or discharge from the container is shut off, the container is given a settable negative or overpressure relative to atmospheric pressure, and the gas mass flow required for this (gas mass flow) ) The airtightness inspection method according to the invention of a tank device and a tank venting device of a motor vehicle equipped with a container, in particular an internal combustion engine, in which a first signal representing in particular an air mass flow rate is measured, achieves a constant negative or overpressure. The gas mass flow (gas mass flow) is controlled in such a way that a non-hermetic presence is assumed when an average constant gas mass flow rate is set, which is greater than a settable limit value. Designed to be Here, only in the presence of non-hermeticity, the gas mass flow rate for maintaining the negative or overpressure must be constantly adjusted, so it is advantageous to set a constant gas mass flow rate. A decrease in negative pressure due to gas generation and / or deformation of the elastic part of the container, in particular the tank, in particular contraction, or a reduction of overpressure due to condensation of the gas or gas mixture and / or expansion of the elastic part of the container, over time. Decrease. Inferring non-hermetic only when a certain gas mass flow rate is greater than the limit value so that a slight pressure drop due to slight gas generation or slight condensation is not mistakenly diagnosed as non-hermetic Is advantageous.

  This limit is set as a function of the elasticity of the container and / or the residual evaporation of at least one fluid in the container or the residual condensation of at least one component of the gas mixture, which clearly improves the accuracy of the gas tightness check. It is advantageous that

In order to maintain a negative or overpressure, it is advantageous to adjust the discharge capacity of the pressure source that is inherently present.
In particular, in the case of a vent valve (in other words, a gas vent valve) connected to the intake pipe of the internal combustion engine, particularly in a container having a tank vent valve, the negative pressure can be controlled very easily by changing the opening of the vent valve. It is advantageous to be able to infer non-tightness or to calculate non-tightness variables from the operating variables in which the vent valve is operated.

  The container tightness inspection apparatus according to the present invention is capable of controlling the pressure source to maintain a constant negative pressure or overpressure that can be set on average, and an operating variable that can operate the pressure source for control. From, it is designed to be able to calculate non-hermetic variables. By using a controllable pressure source, it is possible to maintain a constant negative or overpressure regardless of gas generation or condensation and / or the elasticity of the vessel components.

It is preferred that the pressure source is controlled by the control unit, in particular by the engine control device which is naturally present, so that no additional structural parts are required.
Advantageously, the pressure source is an electromagnetically driven pump and the pump current can be determined very easily as an operating variable.

  Other advantages and features of the invention will be apparent from the following description of the preferred embodiments of the invention and the drawings.

  In the following, the method according to the invention will be described by means of a tank device having a tank 10 in an automobile equipped with an internal combustion engine, as shown in FIGS. This method is not limited to the tank 10 of an automobile, but rather in any vessel or tank device for various fluids, especially fuel, and in particular in the tank ventilation system of tank devices in various fields, for example in the chemical industry. Can be used for airtight inspection.

  The tank 10 shown schematically in FIG. 1 to be inspected for airtightness has a fresh air supply line 40 in which a controllable shut-off valve 50 is arranged. Fresh air can flow into the tank 10 in the direction of the arrow 45 via the fresh air supply pipe 40. Further, the tank 10 has a suction pipe 20, and an electromagnetically driven vacuum pump (pump 30) is disposed in the suction pipe 20. Instead of the pump 30, for example, a mechanically driven and / or hydraulically driven vacuum source may be provided.

  The gas mixture 12 is sucked from the tank 10 by the pump 30 through the suction pipe 20 in the direction of the arrow 25. The pump 30 can be operated and controlled by a control unit 70, particularly an engine control device, via a control line 35. Further, the control unit 70 can open and close the shut-off valve 50 via the control line 55.

  Furthermore, the tank 10 has a pressure sensor 60, and the pressure in the tank 10 can be measured by the pressure sensor 60. Obviously, the pressure sensor 60 may be arranged at other positions in the tank apparatus where the same pressure is applied. The signal from the pressure sensor 60 is transmitted to the control unit 70 via the signal line 65.

Instead of using the pressure sensor 60, the pressure may be determined in other ways, for example from any operating variable of the tank device and / or the pump 30 that represents the characteristics of the pressure sensor.
The tank 10 is at least partially filled with fuel 11, as shown by way of example in FIG. Above the fuel 11 is a gas mixture 12. The gas mixture 12 particularly comprises fuel vapor and air. The tank may be filled only with the gas mixture 12.

  In the second embodiment shown in FIG. 2, the same components as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals. The description of the embodiment is directly referred to. This embodiment differs from the first embodiment in that a controllable tank vent valve 30 ′ is provided instead of the pump 30, and the gas mass flow rate in the suction pipe 20 is controlled by the tank vent valve 30 ′. Is possible. Here, the suction pipe 20 is coupled to an intake pipe of an internal combustion engine (not shown). When the internal combustion engine is operating, the gas mixture 12 is drawn from the tank 10 in the direction of the arrow 25 due to the negative pressure in the intake pipe if the tank vent valve 30 ′ is at least partially open.

  Here, the shut-off valve 50 is closed and the gas mixture 12 is allowed to pass through the suction pipe 20 by opening the tank vent valve 30 'shown in FIG. 2 by the pump 30 shown in FIG. When sucked, a negative pressure is formed in the tank device, particularly in the tank 10.

Here, in order to carry out a tightness check according to the invention, the method starts from step 20, as shown in FIG.
First, in step 210, the shut-off valve 50 is closed, whereby the fresh air supply pipe 40 is shut off, and therefore fresh air cannot flow into the tank 10.

  Subsequently, in step 220, the negative pressure in the tank 10 is controlled. For this purpose, the pump 30 or tank vent valve 30 ′ is operated as shown in FIGS. 1 and 2 and a negative pressure is created in the tank 10. In this case, the negative pressure is controlled to a predetermined constant value set on the manufacturer side, for example.

This control process compensates for negative pressure drop due to gas generation of the fuel 11 and / or deformation of the elastic components of the tank device, for example contraction. Therefore, a decrease in the gas mass flow rate appears in the time diagram, and this decrease in the gas mass flow rate decreases the discharge capacity of the pump 30 necessary to maintain the negative pressure or the opening degree of the tank vent valve 30 '. Can be detected.
When non-tightness exists in the tank device, as soon as the gas generation of the fuel 11 is almost finished, a constant air mass flow rate is set on a constant basis due to non-tightness by a negative pressure controlled to be constant. Is done. The residual evaporation of the fuel 11 contributes only slightly to the negative pressure drop.
Since the elastic component does not contract any further, this does not further reduce the negative pressure. Since the gas mass flow rate in the suction pipe 20 is a substantially constant air mass flow rate, it is in a steady state.

  The pump 30 or the tank vent valve 30 ′ is operated with an average operating variable in the steady state, which in this case is the operating variable in the tank 10 determined by the pressure sensor 60 in the control unit 70. From the signal for the pressure, it is determined in a manner known per se. Here, the manipulated variable is, for example, a pump current. However, the rotational speed or the like may be used as the operation variable here. The electromagnetic operation tank ventilation device 30 'may be operated periodically, for example, and at this time, the cycle frequency is an operation variable.

  Here, in step 230, it is checked whether the gas mass flow rate is greater than a configurable limit value, which is determined in advance by experiments, for example, and set by the manufacturer, for example. Is specific to the physical and / or chemical properties of the tank apparatus or fuel 11, for example the residual evaporation of the fuel 11. If the gas mass flow rate is not greater than the set limit value, it is inferred in step 240 that there is no non-tightness, i.e. inflow of air from the surroundings due to non-tightness in particular. Subsequently, the method ends at step 280.

  On the other hand, if it is determined in step 230 that the gas mass flow rate is greater than the set limit value, in step 250 it is assumed that non-hermeticity exists. Subsequently, in step 260, a non-hermetic variable is calculated from the manipulated variable determined in step 220.

The calculated non-tightness variable is transmitted in step 270 to an output unit or control unit 70 not shown.
Subsequently, in step 280, the method ends.

  An overpressure may be formed in the tank 10 instead of the negative pressure. For this reason, a corresponding overpressure source is required instead of the pump 30 or the tank vent valve 30 '. In this case, condensation of the gas mixture 12 can be compensated for instead of gas generation.

  As described above, the above embodiment relates to an airtight inspection method for a container (particularly, an automobile tank device). Conventionally, there has been a method of diagnosing by pressurizing a tank to measure a pressure drop or providing a reference leak in parallel. There was also a method of making a negative pressure and diagnosing from the pressure increase. In the case of a negative pressure, fuel evaporation and elastic deformation (shrinkage) of the tank itself become measurement errors. When pressurization is performed, condensation of the gas mixture and elastic deformation (expansion) of the tank itself become diagnostic errors. The above-described embodiment is a method and apparatus that eliminates this error factor. The gas mass flow rate is controlled by the vacuum pump 30 or the intake pipe vent valve 30 ′ so that a constant negative pressure is achieved in the tank, and the non-hermeticity of the tank is estimated when the gas mass flow rate is larger than the limit value. Is done. From the constant gas mass flow rate, a non-hermetic variable can be calculated. The limit value can be set as a function of the elasticity of the vessel, the residual evaporation of the fluid, the residual condensation of the gas mixture. A pump can be used to create a constant pressure in the tank. An example using the pump is the first embodiment (FIG. 1), an example using the intake pipe vent valve is the second embodiment (FIG. 2), and FIG. 3 shows a flow chart of the tank airtightness inspection method.

  As described above, the above embodiment is implemented in the container (10, 20, 30, 40, 50), in particular, the method and apparatus for airtight inspection of a tank device and a tank ventilation device of an automobile equipped with an internal combustion engine. And / or the non-tightness of the container (10, 20, 30, 40, 50) can be detected with high certainty and the non-tightness variable can be determined with high accuracy independently of the chemical process. The components of the container (10, 20, 30, 40, 50), in particular the elasticity of the tank (10) and / or the gas generation of the liquid (11) present in the container (10, 20, 30, 40, 50) Or the influence of the condensation of the gas or gas mixture (12) present in the vessel (10, 20, 30, 40, 50) on the negative or overpressure in the vessel (10, 20, 30, 40, 50). To reduce The gas mass flow is controlled so that a constant negative or overpressure is achieved in the container (10, 20, 30, 40, 50) and is on average constant greater than a settable limit value. When the gas mass flow rate is set, the presence of non-hermeticity is assumed. From the signal representing a constant gas mass flow rate, a non-hermetic variable is calculated.

  In this way, the impact of the elasticity of the container components and / or the gas generation of the liquid present in the container or the condensation of the gas or gas mixture present in the container on the negative or overpressure in the container is reduced. This makes it possible to detect the non-tightness of the container with a high degree of certainty and to determine the non-tightness variable with high accuracy, irrespective of the physical and / or chemical process being performed, in particular Provided are a tank apparatus for an automobile equipped with an internal combustion engine and a method and apparatus for airtight inspection of a tank ventilation apparatus.

FIG. 1 is a schematic diagram of a first embodiment of a tank apparatus with a vacuum pump in which the method used according to the invention is used in that embodiment. FIG. 2 is a schematic diagram of a second embodiment of a tank apparatus with a tank vent valve in which the method used according to the invention is used in that embodiment. FIG. 3 is a schematic flowchart of the tank airtight inspection in the tank apparatus of FIG. 1 or 2.

Explanation of symbols

10 Tank 11 Fluid (fuel)
12 Gas mixture 20 Suction piping 25 Suction (arrow)
30 Pump (pressure source)
30 'Ventilation valve (in other words, venting valve)
35, 55 Control line 40 Fresh air supply piping (ie, outside air supply piping)
45 Supply (arrow)
50 Shut-off valve 60 Pressure sensor 65 Signal line 70 Control unit

Claims (12)

Are each discharged (45) cut off from the supply to the vessel to the container, the container, which can be set, a negative pressure or overpressure is given to atmospheric pressure, and a gas mass flow amount required for this in the first signal is measured, airtightness inspection method of a container of a motor vehicle tank system and tank venting apparatus having an inner combustion engine representing,
In so that the is such a constant negative pressure or overpressure container, gas mass flow rate is controlled,
Greater than settable limit value, when the constant gas mass flow rate on average is set, airtightness inspection method of a container, characterized in that the presence of non-airtight is inferred. The method of claim 1, wherein
Said limit value is set as a function of the elasticity of the container and / or the residual evaporation of at least one fluid (11) in the container or the residual condensation of at least one component of the gas mixture (12). that way. The method of claim 1 or 2,
How you characterized in that the signal representing the constant gas mass flow rate, a non-airtight variables are calculated. The method according to any one of claims 1 to 3,
In order to control the gas mass flow, the discharge capacity of the pressure source (30; 30 ') is varied and a variable representing the discharge capacity is measured as a first signal representing the gas mass flow. that way. The method according to any one of claims 1 to 3,
To provide a negative pressure, it is controlled flow rate of the vent valve (30 '), and a variable representing the flow rate, how you being determined as a first signal representative of the gas mass flow. 6. The method of any of claims 4 or 5,
Calculated manipulated variable for manipulating the pressure source (30) to vent valve (30 ') as a function of the pressure signals, and how you characterized in that non-airtight variable is determined from the operation variable. Shut-off valve for blocking the discharge (45) from to no supply to the container vessel (50), the container, configurable, vacuum or pressure source capable of providing the over-pressure with respect to atmospheric pressure ( 30; 30 ') and equipped with, to 請 Motomeko no 1 for performing the method of any of 6, the leak test apparatus containers automobile tank unit and tank venting apparatus having an inner combustion engine,
The pressure source (30; 30 ') is controllable to maintain a settable average constant negative or overpressure in the container , and for control purposes the pressure source (30; 30') ) Can be calculated from manipulated variables that can be manipulated,
An air tightness inspection device for containers. The apparatus of claim 7.
Equipment you characterized by comprising a control unit (70) for controlling, (30 '30) pressure source. The device of claim 7 or 8,
A pressure source (30) is electromagnetically driven pump, equipment you characterized in that the pump current is manipulated variables. The apparatus according to any one of claims 7 to 9,
Pressure source; includes (30 30 ') of the vent valve (30' a), in order to control the negative pressure, equipment you characterized by a degree of opening of the vent valve (30 ') can be controlled. A method according to any of claims 1 to 6,
  The container has a pressure sensor, and the pressure in the container can be measured by the pressure sensor so that the inside of the container has a constant negative pressure or overpressure based on the pressure in the container measured by the pressure sensor. Wherein the gas mass flow rate is controlled. The method of claim 11, wherein
  The container has a suction pipe, a pressure source is disposed in the suction pipe,
  A method of controlling a gas mass flow rate in a suction pipe with a pressure source so that a constant negative pressure or overpressure is generated in a container.

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